Treatment Of Cutaneous T-cell Lymphoma Research Articles

Vorinostat-Induced Apoptosis in Mantle Cell Lymphoma Is Mediated by Acetylation of Proapoptotic BH3-Only Gene Promoters

Mantle cell lymphoma (MCL) is an aggressive B-cell neoplasm with generally poor prognosis, for which current therapies have shown limited efficacy. Vorinostat is a histone deacetylase inhibitor (HDACi) that has been approved for the treatment of cutaneous T-cell lymphoma. Our purpose was to describe the molecular mechanism whereby vorinostat induces apoptosis in MCL with particular emphasis on the role of proapoptotic BH3-only proteins. The sensitivity to vorinostat was analyzed in eight MCL cell lines and primary cells from 10 MCL patients. Determination of vorinostat mechanism of action was done by flow cytometry, immunoblotting, HDAC activity assay kit, quantitative reverse transcription PCR, chromatin immunoprecipitation, and siRNA-mediated transfection. Vorinostat inhibited total histone deacetylase activity leading to selective toxicity toward tumor cells. Vorinostat-mediated cell death implied the activation of mitochondrial apoptosis, as attested by BAX and BAK conformational changes, mitochondrial depolarization, reactive oxygen species generation, and subsequent caspase-dependent cell death. This phenomenon was linked to H4 hyperacetylation on promoter regions and consequent transcriptional activation of the proapoptotic BH3-only genes BIM, BMF, and NOXA. Selective knockdown of the three corresponding proteins rescued cells from vorinostat-induced apoptosis. Moreover, vorinostat enhanced the activity of the BH3-mimetic ABT-263 in MCL cells, leading to synergistic apoptosis induction. These results indicated that transcriptional upregulation of BH3-only proteins plays an important role in the antitumoral activity of vorinostat in MCL, and that HDACi alone or in combination with BH3-mimetizing agents may represent a promising therapeutic approach for MCL patients.

Romidepsin (Istodax, NSC 630176, FR901228, FK228, depsipeptide): a natural product recently approved for cutaneous T-cell lymphoma

Romidepsin (Istodax), a selective inhibitor of histone deacetylases (HDACs), was approved for the treatment of cutaneous T-cell lymphoma in November 2009 by the US Food and Drug Administration. This unique natural product was discovered from cultures of Chromobacterium violaceum, a Gram-negative bacterium isolated from a Japanese soil sample. This bicyclic compound acts as a prodrug, its disulfide bridge being reduced by glutathione on uptake into the cell, allowing the free thiol groups to interact with Zn ions in the active site of class I and II HDAC enzymes. Due to the synthetic complexity of the compound, as well as the low yield from the producing organism, analogs are sought to create synthetically accessible alternatives. As a T-cell lymphoma drug, romidepsin offers a valuable new treatment for diseases with few effective therapies.

Abstract 4396: Evaluation of gene expression and transcriptional activation in patients treated with vorinostat

Abstract Background: Vorinostat is a histone deacetylase (HDAC) inhibitor that is approved for treatment of cutaneous T-cell lymphoma and is being investigated in a number of solid tumors. Inhibition of HDAC by vorinostat leads to an accumulation of acetylated histones which induces apoptosis though a mechanism that is not completely characterized. This study was performed to assess the potential mechanisms responsible for induction of apoptosis following treatment with vorinostat. Methods: Sixty subjects with advanced malignancies received vorinostat orally days 1-14 combined with bortezomib IV on days 2, 4, 8, and 11 of a 21-day cycle. Peripheral blood mononuclear cells (PBMCs) were collected before and 2hr and 6hr after dosing on Days (D) 1 and 9. Paired tumor biopsies were obtained in ten patients on D0 and D9. Gene expression of downstream targets was evaluated by semi-quantitative RT-PCR in PBMCs, and the interaction between candidates genes and acetylated histone H3 were evaluated in biopsies by the chromatin precipitation assay. A nonparametric Wilcoxon signed rank test was used to examine changes from the pre-treatment value of 1 on D1 based on complete case analysis without multiplicity adjustment. Results: p21, Nur77 and HSP70 gene expression in PBMCs were all significantly induced two hours after vorinostat administration compared to baseline (Table 1). AKT, ERB1 and ERB2 expression were not statistically significantly altered in PBMCs. The expression of all targets increased in tumor biopsies by Day 9, with p21 2.37, Nur77, 1.33 and HSP70 2.35 times baseline expression levels. The chromatin precipitation assay demonstrated that Nur77, HSP70 and p21 interacted with acetylated histone H3, after nine days of treatment with vorinostat, in tissue biopsies. Conclusion: This data suggests that acetylated histones interact transcriptionally with p21, Nur77 and HSP77 to induce gene expression and are a potential mechanism by which vorinostat induces apoptosis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4396. doi:10.1158/1538-7445.AM2011-4396

Abstract 5418: Thailandepsins: Novel bacterial natural products with potent histone deacetylase inhibition activities and promising anticancer activities

Abstract Epigenetic abnormalities participate with genetic mutations to cause cancer; consequently epigenetic intervention of cancer has emerged as a promising avenue toward cancer therapy, with one synthetic compound verinostat (SAHA, Zolinza® by Merck & Co.) and one natural product FK228 (depsipeptide, romidepsin, Istodax® by Gloucester Pharma) already approved by FDA for the treatment of cutaneous T-cell lymphoma. FK228 represents a small family of natural products, all of which are produced by Gram-negative bacteria, and each of which contains a signature disulfide bond that mediates a novel mode of anticancer action. The overall goal of our research is to explore naturally produced and metabolically or chemically modified histone deacetylase (HDAC) inhibitors as anticancer lead compounds. Our studies of the biosynthesis of FK228 in Chromobacterium violaceum No. 968 and the related spiruchostatin in Pseudomonas sp. Q71576 have led to the discovery of thailandepsin A and thailandepsin B, two novel natural analogs of FK228 and spiruchostatins, from the culture broth of Burkholderia thailandensis E264. HDAC inhibition assay shows that thailandepsins have as potent inhibitory activities as FK228 toward human HDAC1, HDAC2, HDAC3, HDAC6, HDAC7, HDAC8 and HDAC9; but there is a significant differentiation between FK228 and thailandepsins toward HDAC4, underlining potentially differential anticancer activities. NCI60 anticancer screening shows that thailandepsins possess a broad spectrum of growth inhibition activities, and have reached GI50 for over 90% of the tested cell lines even at the lowest concentration (10-8M) used in the screening. Most interestingly, thailandepsins demonstrated differential activities toward certain types of cell lines at TGI and LC50 levels, particularly for those derived from colon, melanoma and renal cancers. Thailandepsins therefore represent additional naturally produced HDAC inhibitors that are promising for anticancer drug development. We seek further collaborations to address the detailed pharmacological effects of thailandepsins on cancer biology. In addition, with access to three homologous biosynthetic pathways that collectively produce five structural analogs, we have now established an excellent platform for combinatorial biosynthesis and chemical derivatization of a library of FK228-family “un-natural” natural products for anticancer drug discovery and development. Supports for this research were from the University of Wisconsin-Milwaukee, the US Department of Defense Breast Cancer Research Program and the US National Institute of Health/National Cancer Institute. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5418. doi:10.1158/1538-7445.AM2011-5418

Abstract 2614: Inhibition of class I histone deacetylases attenuates anthracycline induced activation of the ATM pathway

Abstract Breast cancer is one of the most common cancers to afflict women in the world. Anthracycline-based regimens, including doxorubicin and epirubicin (epidoxorubicin), are common therapies for patients with breast cancer. Doxorubicin and epirubicin are inhibitors of topoisomerase II, which cause double strand DNA breaks. Following anthracycline-induced damage, DNA damage response pathways are activated in order to initiate cell cycle arrest, DNA repair, and/or cell death. The recent introduction of PARP inhibitors highlights the clinical relevance of targeting DNA repair pathways in treating this disease. Recently, two histone deacetylase (HDAC) inhibitors have been approved by the Federal Drug Administration for the treatment of cutaneous T-cell lymphoma: vorinostat and romidepsin. HDAC inhibitors reduce the repair of DNA, and are being used in combination with DNA damaging chemotherapeutic agents. The mechanisms regulating the HDAC inhibitor-mediated reduction of DNA repair in breast cancer cells are not well established. Understanding these mechanisms will identify key therapeutic targets for reducing DNA repair, define the role of HDACs in DNA repair, and allow for the enrichment of patients most susceptible to HDAC inhibitor-chemotherapy combined treatment. Previously, our group has demonstrated an increase in DNA decondensation which permits greater access of anthracyclines to DNA after therapeutic inhibition of HDACs. New results demonstrate that phosphorylation of p53 at Serine 15 is decreased in the presence of epirubicin after pre-treatment with vorinostat in a time- and concentration-dependent manner. Total p53 protein levels are also decreased, while mRNA levels remain unchanged after combined treatment. Treatment of breast cancer cells with valproic acid or entinostat also attenuates phosphorylation of p53 after epirubicin treatment, suggesting the involvement of Class I HDACs in the activation of p53. Phosphorylation of DNA repair kinase ATM is also decreased following DNA damage in the presence of clinically relevant concentrations of vorinostat, and corresponds with a decrease in activation of downstream factors including CHK1, CHK2, and BRCA1. These results demonstrate that inhibition of Class I HDACs in breast cancer cells delays DNA damaging response signaling through p53 modification after anthracycline administration; suggesting a possible mechanism for synergy between HDAC inhibitors and DNA damaging agents. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2614. doi:10.1158/1538-7445.AM2011-2614

Abstract 597: The cellular and genomic response to histone deacetylase inhibitors in diffuse large b-cell lymphoma

Abstract Diffuse Large B-cell lymphoma (DLBCL) is the most frequent subtype of Non-Hodgkin Lymphoma (NHL) in all countries around the world and in all age groups. Several drug regimens have been used in treatment of DLBCL; however, this disease remains eventually fatal in 30 – 40% of the patients. Chemotherapy resistance can be partly explained by the fact that DLBCL is a heterogeneous group of NHLs, with the two most prevalent subtypes being “Activated B-cell Like” (ABC) and “Germinal Center B-cell like” (GCB). Patients with the ABC subtype have the poorest prognosis under the current treatment regimen. Therefore, there is a pressing need for new therapeutics that can increase survival rates in DLBCL patients. Histone deacetylase inhibitors (HDIs) have proven to be promising drugs in the treatment of blood malignancies. Even though their mechanism of action has not been fully characterized, two HDIs, (Vorinostat and Romidepsin) have been approved for the treatment of cutaneous T-cell lymphoma (CTCL). Therefore the purpose of the current study is to investigate the response of DLBCL subtypes to HDIs, with a particular focus on subtype-specific mechanisms of action. Our current working hypothesis is that a comprehensive analysis of the genomic and proteomic response to histone deacetylase inhibitors (HDIs) including gene expression and transcription factor acetylation will reveal both mechanisms and potential biomarkers of HDI action in lymphomas DLBCL. In the current study we have focused on the cellular and genomic effects of the hydroxamate HDI, Belinostat (PXD101), on cell lines representing the GCB subtype of DLBCL. We show that PXD101 inhibits growth of four GCB-type cell lines with 24 h IC50s in the low micromolar range (SUDHL6 =0.15uM, OCI Ly19 = 0.3uM, SUDHL4 = 0.45uM, DB = 0.77uM). Flow cytometry analysis has shown that three of these cell lines (SUDHL6, OCI Ly19 and DB) arrest in the G2/M phase of the cell cycle by 24 hours of treatment at the IC50 dose and then die by apoptosis. In contrast, the SUDHL4 cell line reversibly arrests in the G1 phase without undergoing cell death. Western blot analysis of PARP and caspase-3 cleavage has further confirmed the presence/absence of apoptosis. We suggest that the SUDHL4 cell line represents DLBCL tumors that are refractory to the apoptosis-inducing effects of HDIs. Thus, we are using this cell line to identify other therapeutics which could be used in combination with PXD101 to induce cell death.The mechanistic basis for the differential cellular response between the GCB type cell lines is currently under investigation using expression profiling data obtained from OCI Ly19 and SUDHL4 cells treated with PXD101. Preliminary data indicates divergent responses in expression of GADD45 and p21, the Myc/Max family of proteins, and the clock genes, Per1 and Cry2. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 597. doi:10.1158/1538-7445.AM2011-597

Abstract 2629: Sustained immediate-early gene induction is linked to histone deacetylase inhibitor-induced apoptosis in multiple tumour types

Abstract Introduction: Histone deacetylase inhibitors (HDACi) are a novel class of cancer therapeutics, currently approved for the treatment of cutaneous T-cell lymphoma (CTCL) and undergoing clinical trials for other haematological and solid tumours. Through screening of a panel of 30 colorectal cancer cell (CRC) lines, we previously established that HDACi-induced apoptosis is linked to a specific transcriptional response consisting of induction of multiple immediate-early (IE) and stress response genes. The purpose of this study was to investigate whether the findings made in colorectal cancer cells are applicable to other tumor types and to further elucidate the mechanism of apoptosis induction involving IE genes. Results: We screened a panel of 40 tumor cell lines including that of CTCL, multiple myeloma, NSCLC, melanoma, breast and prostate cancer, for HDACi (sodium butyrate and Vorinostat) sensitivity by PI/FACS analysis and identified highly sensitive and resistant cell lines. Consistent with the findings made in CRCs, quantitative RT-PCR analysis revealed that the expression of six representative IE genes (Fos, Jun, Atf3, Egr1, Egr3, Gadd45b) were preferentially induced by HDACi treatment in the 5 most sensitive cell lines compared to the 5 most refractory tumor cell lines. To study kinetics of IE gene induction, we performed time-course experiments on cancer cell lines treated with various stimuli, including EGF, phorbol ester PMA, and HDACi. While EGF and PMA induce IE gene expression in a rapid and transient manner, HDACi-induction of IE gene expression is sustained over 24 hours, suggesting that the prolonged expression of these genes may be responsible for apoptosis induction. By transient transfection of siRNA into tumour cell lines, we demonstrated that the down-regulation of the IE genes Jun and Atf3 partially blocks HDACi-induced apoptosis. Conclusions: We demonstrated that HDACi-induced apoptosis is linked to sustained transcriptional induction of multiple IE genes in a variety of cancer cells. Furthermore, we demonstrated that IE genes of the AP-1 transcription factor family Jun and Atf3 are directly involved in the apoptosis response induced upon HDACi treatment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2629. doi:10.1158/1538-7445.AM2011-2629

Romidepsin in the treatment of cutaneous T-cell lymphoma

The most common subtypes of primary cutaneous T-cell lymphoma (CTCL) are mycosis fungoides and Sézary syndrome. Clinical manifestations and prognosis in CTCL are highly variable. Improving the management of this incurable disease with limited toxicity is an active area of research. Romidepsin is a novel, well-tolerated histone deacetylase inhibitor with promising activity against advanced stages of CTCL. In November 2009, it was approved by the US Food and Drug Administration for the treatment of CTCL in patients who have received at least one prior systemic therapy. This review focuses on the activity, pharmacology, and safety of romidepsin for the treatment of CTCL.

Comparison of pegylated interferon α‐2b plus psoralen PUVA versus standard interferon α‐2a plus PUVA in patients with cutaneous T‐cell lymphoma

The aim of this study was to evaluate the safety and efficacy profile of pegylated interferon α-2b (PEG-IFN α-2b) in combination with photochemotherapy (PUVA) in the treatment of cutaneous T-cell lymphoma (CTCL) in comparison with standard IFN α plus PUVA. Retrospective cohort study over a period of 7 years. A total of 17 consecutive CTCL patients (stage IA-IV) were retrospectively analysed for toxicity and response rates associated with PEG-IFN α-2b (1.5 μg/kg weekly) plus PUVA (n = 9) or standard IFN α-2a (9 MIU 3×/week) plus PUVA (n = 8). Differences of response rates (complete/partial remission), progression-free survival, discontinuation of therapy, safety and toxicity profiles according to World Health Organization - Common Terminology Criteria of Adverse Events (WHO-CTCAE). Myelosuppression and liver toxicity occured more frequently during PEG-IFN α-2b plus PUVA treatment than during standard IFN α-2a plus PUVA therapy [77.8 vs. 50% (odds ratio 1.477) and 77.8 vs. 50% (odds ratio 1.692), respectively]. By contrast, the occurence of constitutional side-effects (mainly fatigue) [100 vs.77.8% (odds ratio 0.889)] and more adverse events leading to study discontinuation was considerably higher in the standard IFN α-2a plus PUVA group. The overall response rate in the PEG-IFN α-2b plus PUVA group (89%) was significantly superior. In patients with cutaneous T-cell lymphoma PEG-IFN α-2b plus PUVA might become a promising treatment alternative as its higher rate of myelosuppression and liver toxicity is outweighed by its lower percentage of constitutional side-effects, and its significantly higher overall response. Due to the small number of participants at this retrospective study, a larger prospective study is essential to verify our results.

The histone deacetylase inhibitors vorinostat and romidepsin downmodulate IL‐10 expression in cutaneous T‐cell lymphoma cells

Vorinostat and romidepsin are histone deacetylase inhibitors (HDI), approved for the treatment of cutaneous T-cell lymphoma (CTCL). However, the mechanism(s) by which these drugs exert their anti-cancer effects are not fully understood. Since CTCL is associated with immune dysregulation, we investigated whether these HDI modulated cytokine expression in CTCL cells. CTCL cell lines and primary CTCL cells were treated in vitro with vorinostat or romidepsin, or with STAT3 pathway inhibitors. Cell cycle parameters and apoptosis were analysed by propidium iodide and annexin V/propidium iodide staining respectively. Cytokine expression was analysed using QRT-PCR and elisa assays. STAT3 expression/phosphorylation and transcriptional activity were analysed using immunoblotting and transfection/reporter assays respectively. Vorinostat and romidepsin strongly down-regulated expression of the immunosuppressive cytokine, interleukin (IL)-10, frequently overexpressed in CTCL, at both the RNA and protein level in CTCL cell lines and at the RNA level in primary CTCL cells. Vorinostat and romidepsin also increased expression of IFNG RNA and decreased expression of IL-2 and IL-4 RNA, although to a lesser extent compared to IL-10. Transient exposure to vorinostat was sufficient to suppress IL-10 secretion but was not sufficient to irreversibly commit cells to undergo cell death. STAT3 pathway inhibitors decreased production of IL-10 and vorinostat/romidepsin partially decreased STAT3-dependent transcription without effects on STAT3 expression or phosphorylation. These results demonstrate that HDI modulate cytokine expression in CTCL cells, potentially via effects on STAT3. Immunomodulation may contribute to the clinical activity of HDI in this disease.

Rational Therapeutic Combinations with Histone Deacetylase Inhibitors for the Treatment of Cancer

Histone deacetylases (HDACs) regulate the acetylation of a variety of histone and nonhistone proteins, controlling the transcription and regulation of genes involved in cell cycle control, proliferation, survival, DNA repair and differentiation. Unsurprisingly, HDAC expression is frequently altered in hematologic and solid tumor malignancies. Two HDAC inhibitors (vorinostat and romidepsin) have been approved by the US FDA for the treatment of cutaneous T-cell lymphoma. As single agents, treatment with HDAC inhibitors has demonstrated limited clinical benefit for patients with solid tumors, prompting the investigation of novel treatment combinations with other cancer therapeutics. In this article, the rationales and clinical progress of several combinations with HDAC inhibitors are presented, including DNA-damaging chemotherapeutic agents, radiotherapy, hormonal therapies, DNA methyltransferase inhibitors and various small-molecule inhibitors. The future application of HDAC inhibitors as a treatment for cancer is discussed, examining current hurdles to overcome before realizing the potential of this new approach.

Next generation histone deacetylase inhibitors: the answer to the search for optimized epigenetic therapies?

Introduction: HDAC inhibitors have demonstrated potent anticancer activities in preclinical and clinical studies. Currently, two drugs (SAHA and romidepsin) have gained the FDA approval for the treatment of cutaneous T-cell lymphoma. Clinical efficacy of HDAC inhibitors has been observed in advanced hematological malignancies, while response in other cancers has been in most cases unpredictable and often rather limited. The search for new molecules with the potential to overcome the limitations of the first HDAC inhibitors has become a primary goal in the field of epigenetic drug discovery as well as drugs acting on other chromatin modifying enzymes.Areas covered: The article shortlists seven new HDAC inhibitors that have recently entered clinical studies as representative examples of next generation drugs. The most recently published preclinical profile is reviewed, together with the first clinical data for these compounds. The article then focuses on challenges faced during the progress of first generation HDAC inhibitors and analyzes whether these new compounds are likely to provide a solution to the existing issues and needs.Expert opinion: Next generation HDAC inhibitors have the ‘best-in-class’ potential, particularly regarding potency and in vivo exposure. However, several issues remain unresolved. For example, none of the presented compounds appears to have a significantly different selectivity profile towards various HDAC isoforms and, thus, none of them may provide a further elucidation between the toxicity seen in more advanced HDAC inhibitors and isoform selectivity. Additionally, a need for a continuous effort on target validation is seen as a necessary requirement for further progress in the field.

Interactions of bexarotene (LGD1069, Targretin) with the coagulation system

Bexarotene, (LGD1069, Targretin), is an antitumoral agent used as chemotherapy in the treatment of cutaneous T-cell lymphoma. Therapy with bexarotene is accompanied by adverse events, such as, bleeding, hemorrhage, and coagulopathy In order to design applications for bexarotene, it was very important to gain an understanding of how bexarotene inhibits blood clotting We investigated the interaction between bexarotene or vehicle alone, and coagulation factors or blood cells. We used both in vitro and in vivo assays. Anticoagulant activity of bexarotene or vehicle was assessed by clotting time tests (TT, RT, APTT, and PT). Coagulation factors activity was measured by adding diluted test plasma to artificially prepared factor-deficient plasma. Direct interactions between bexarotene and factor Xa were studied by chromogenic substrate assay. A mouse model was used to investigate in vivo effects of the drug on blood system and for evaluation of clinical hematology and organ pathology. Increases in clotting times (prothrombin time and activated thromboplastin time) occurred with bexarotene in in vitro and in vivo experiments. We detected no significant influence of bexarotene on factors II, V, VII, VIII, XI and XII, while factor IX and factors X were affected. Bexarotene exerts anticoagulant effects and acts mainly as a direct factor IX and factor X inhibitor. On the contrary, the vehicle is remarkably inert toward the coagulation system. The number of blood cells was unaffected in mice treated with bexarotene or with the vehicle. Monitoring of the coagulation factors profile should be considered in cancer patients receiving bexarotene, particularly those with a known diagnosis of coagulation factors deficient.

Cutaneous T-Cell Lymphoma

Cutaneous T-Cell Lymphoma

Molecular Markers Associated with Clinical Response to Bexarotene Therapy in Cutaneous T-cell Lymphoma

Bexarotene (Targretin(®)), was registered for the treatment of cutaneous T-cell lymphoma (CTCL) in 2002, and has been reported to induce a 45% overall response. Responses are mostly partial or generate a stable, skin-restricted disease. This study explored the usefulness of a novel cancer-associated gene, NAV3 and corresponding chromosome 12 copy numbers as possible biomarkers to monitor the therapeutic response to bexarotene in 21 Finnish patients with CTCL. Six patients (29%) reached complete remission (CR) and 3 of these remained in CR for more than 24 months, 12 (57%) reached a partial response (PR, with one stable disease) and 3 were non-responders. Low-level NAV3 deletions were detected using a fluorescence in-situ hybridization (FISH) assay in the lesions of 5 patients, 4 of whom were non-responders or progressed after short PR. This occurrence of NAV3 deletions was statistically significant compared with non-progressors (p = 0.011, Fisher's exact test). Chromosome 12 tetraploidy was found in the lesions of two of the 3 patients with CR who remained in remission. While such tetraploidy is a feature of proliferating normal T cells, this observation may reflect a favourable anti-tumour immune response among the skin-infiltrating lymphocytes.

Reduction of Fas/CD95 Promoter Methylation, Upregulation of Fas Protein, and Enhancement of Sensitivity to Apoptosis in Cutaneous T-Cell Lymphoma

To explore the relationships among (Fas) promoter methylation, Fas expression, and apoptotic sensitivity in cutaneous T-cell lymphoma (CTCL). Laboratory investigation. Dermatology research unit of a university medical center. Five CTCL lines and Sézary syndrome blood. Treatment of cells with 5-azacytidine (aza), methotrexate, and interferon alfa-2b. Fas promoter methylation, Fas expression, and sensitivity to Fas-mediated apoptosis. Fas promoter methylation correlates inversely with the level of Fas transcript, protein, and apoptotic sensitivity in CTCL. Increased DNA methylation also correlates with decreased NFkB (nuclear factor kappa-light chain enhancer of activated B cells) binding to the Fas promoter. All of these relationships were reversed by the DNA-demethylating agent, 5-aza. We found that methotrexate also functions as a DNA-demethylating agent by depleting methyl donors and, together with interferon alfa-2b, upregulates Fas and enhances sensitivity to Fas-mediated apoptosis. These findings help explain the previously reported impressive responses of patients with advanced CTCL to combination therapy with methotrexate and interferon alfa. They also provide a new rationale for the treatment of CTCL with methotrexate and its use in combination with other agents.

Final Results From a Pivotal, Multicenter, International, Open-Label, Phase 2 Study of Romidepsin In Progressive or Relapsed Peripheral T-Cell Lymphoma (PTCL) Following Prior Systemic Therapy

AbstractAbstract 114 Background:Romidepsin is a potent HDAC inhibitor approved by the FDA for patients (pts) with cutaneous T-cell lymphoma who have received at least 1 prior systemic therapy. Durable clinical benefit and tolerability of romidepsin in pts with recurrent or refractory PTCL have been previously observed in a phase 2 trial conducted by the National Cancer Institute. The aim of this phase 2, single-arm, open-label registration study was to evaluate the activity of romidepsin in a larger number of pts with progressive or relapsed PTCL. Methods:Pts with histologically confirmed PTCL (PTCL NOS, angioimmunoblastic T-cell lymphoma, ALCL [ALK-1 negative], other subtypes) who failed or were refractory to ≥ 1 prior systemic therapy, and had measurable disease and ECOG performance status 0–2 were eligible. Exclusions included inadequate bone marrow or other organ function and significant cardiovascular abnormalities. Pts received romidepsin 14 mg/m2 as a 4-h IV infusion on days 1, 8, and 15 every 28 days for up to 6 cycles; treatment could be extended for stable disease (SD) or response. The primary endpoint was rate of complete response (CR + CRu) as evaluated by a central Independent Review Committee (IRC) using International Working Criteria for non-Hodgkin's lymphoma. IRC assessment consisted of a 2-step process, with initial radiographic review of images (CT, MRI) followed by an overall clinical assessment based on the radiology evaluations, photographs, and relevant clinical parameters. Secondary endpoints included objective response rate (ORR): CR + CRu + partial response (PR), investigator-assessed responses, duration of response, time to response, and safety. Results:131 pts from 48 US, European, and Australian sites were enrolled and received at least 1 dose of romidepsin (as-treated population); 130 patients had histologically confirmed PTCL by central review. Mean age of all pts was 59.4 y (range, 20–83) and median time since diagnosis was 1.25 y (range, 0–17). Median number of prior systemic therapies was 2 (range, 1–8). 21 pts (16%) had failed a prior stem cell transplant. Responses assessed by the IRC are noted in the table below. Longest duration of response is 26+ mo and 16 (94%) of the 17 pts with a CR had not progressed as of the data cutoff (March 31, 2010). Investigator-assessed responses included 21 pts (16%) with CR + CRu, 18 pts (14%) with PR for an ORR of 30%. Currently, 13 pts continue to receive treatment (range, 10–36 cycles).Adverse events (AEs) were reported in 126 of 131 pts (96%). AEs reported in ≥ 20% of pts were nausea (59%), fatigue (41%), vomiting (38%), thrombocytopenia (38%), diarrhea (35%), pyrexia (34%), neutropenia (30%), anorexia (28%), constipation (28%), anemia (23%), and dysgeusia (21%). AEs ≥ grade 3 were reported for 86 pts (66%), with the most common (≥ 5%) being pneumonia (5%), pyrexia (5%), sepsis (5%), and vomiting (5%). 60 pts (46%) had at least 1 serious AE: the most frequently reported (≥ 5%) were pyrexia (7%), pneumonia (5%), vomiting (5%), and sepsis (5%). 22 pts (17%) withdrew due to AEs. 8 pts (6%) died within 30 days of the last dose of romidepsin; 1 death, due to sepsis, was assessed as possibly related to treatment. Conclusions:Complete and durable responses were observed with single agent romidepsin in pts with relapsed PTCL. These data support the therapeutic potential for romidepsin in relapsed PTCL and suggest that romidepsin is a strong candidate for inclusion in future novel regimens for these diseases.IRC Evaluations (n=130)RadiologyClinicalCR + CRu, n (%)19 (15%)17 (13%)PR, n (%)15 (12%)17 (13%)SD, n (%)36 (28%)32 (25%)ORR (CR + CRu + PR), n (%)34 (26%)34 (26%)Median duration of responseCR + CRu–Not reached(range, 1–801+ days)ORR–12 mo(range, 1–801+ days)Median time to response–3.6 mo(range, 55–169 days)As of the data cutoff (March 31, 2010), the median duration of follow-up for CR is 8.2 mo. Disclosures:Coiffier:Gloucester: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau. Off Label Use: Romidepsin is indicated for the treatment of cutaneous T-cell lymphoma (CTCL) in patients who have received at least one prior systemic therapy. Romidepsin is not currently approved for the treatment of peripheral T-cell lymphoma (PTCL). Pro:Celgene: Research Funding. Prince:Celgene: Consultancy, Honoraria, Research Funding. Foss:Celgene: Consultancy; Eisai: Consultancy, Speakers Bureau; Merck: Speakers Bureau; Allos: Consultancy, Speakers Bureau; Cephalon: Speakers Bureau. Sokol:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Caballero:Celgene: Membership on an entity's Board of Directors or advisory committees. Morschhauser:Roche: Consultancy, Honoraria; Bayer: Honoraria. Padmanabhan:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Shustov:Celgene: Research Funding. Nichols:Celgene: Employment. Carroll:Celgene: Employment. Balser:Gloucester Pharmaceutical: Consultancy. Horwitz:Celgene: Consultancy, Honoraria.

Emerging role of the histone deacetylase inhibitor romidepsin in hematologic malignancies

Importance of the field: Histone acetylation plays a crucial role in chromatin modification and the regulation of gene expression. Histone deacetylase inhibitors (HDACi) are a novel class of antitumor agents with pleiotropic effects; they are under active clinical investigation. The HDACi romidepsin is being evaluated in a variety of tumors and was recently approved for the treatment of cutaneous T-cell lymphomas (CTCL).Areas covered in this review: This review focuses on the findings from early Phase trials involving romidepsin, and the Phase II trial results that led to the approval of romidepsin in CTCL.What the reader will gain: Mechanisms of action of HDACi, including romidepsin, are described in this review and the pharmacodynamic and pharmacokinetic properties of romidepsin are summarized. The efficacy and safety profile of romidepsin in clinical trials in T-cell lymphoma is reviewed, and emerging data on single-agent and combination strategies in myeloid and B-lymphoid malignancies is outlined.Take home message: Romidepsin has significant activity and an acceptable safety profile in CTCL and peripheral T-cell lymphomas. Its use in rationally designed combination approaches is under active investigation in B-lymphoid malignancies.

The Emerging Role of Histone Deacetylase Inhibitors in Treating T-cell Lymphomas

T-cell lymphomas are an uncommon and heterogeneous group of non-Hodgkin lymphomas. Historically, therapies for these diseases have been borrowed from treatments for other lymphomas. More recently, efforts have be made to identify novel agents for their activity specifically in T-cell lymphomas. A primary example of new agents with specific activity in T-cell lymphomas is the novel class of drug, histone deacetylase inhibitors. The potential activity of histone deacetylase inhibitors was discovered somewhat serendipitously, but these early discoveries were followed by some larger and more rigorous studies in T-cell lymphomas. Two compounds, vorinostat and romidepsin, are currently approved and are in clinical use for the treatment of cutaneous T-cell lymphomas. Other drugs are in development, and a large study of romidepsin in peripheral T-cell lymphoma has recently been completed. This review covers data on the use of histone deacetylase inhibitors in T-cell lymphomas, as well as early attempts, just beginning, to combine these agents with other novel therapies.

Confirmation of the biological significance of transthyretin as a biomarker for cutaneous T-cell lymphoma by its protein interaction partners

We previously identified transthyretin (TTR) and its posttranslational modifications as a down-regulated marker in mycosis fungoides (MF), a benign subtype of cutaneous T-cell lymphoma (CTCL). In order to more precisely understand the biological role of TTR in the etiology of MF, it is essential to clarify the pathways of progression by identifying further interacting proteins. This study is the first to combine blue native polyacrylamide gel electrophoresis (BN-PAGE) with surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) to detect new TTR interaction partners and to determine whether these TTR interaction partners can themselves be used as biomarkers. By this procedure, apolipoprotein A1, which was additionally found to be down-regulated in the serum of MF patients, apolipoprotein A4, retinol binding protein4 (RBP-4), and retinoid X receptor β (RXR-β) were identified as interaction partners of TTR. The RXR family plays a role in cell differentiation and proliferation and is known to be the target of bexarotene, which is used in the treatment of CTCL. In conclusion, the combination of BN-PAGE and SELDI-TOF-MS used in this study allowed for the detection of protein interaction partners, which, in the case of RBP-4 and RXR, indicated a connection between the common tumor marker TTR and tumor progression in CTCL.